A LevelChemistryCIETopic Questions1. Atomic Structure1.3 Electrons, Energy Levels & Atomic Orbitals

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First teaching 2023

First exams 2025

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Electrons, Energy Levels & Atomic Orbitals (CIE A Level Chemistry)

Topic Questions

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11 mark

Which of the following statements describes a free radical?

  • A species with a lone pair of electrons

  • A species with a half-filled d-orbital

  • A species with one or more unpaired electrons

  • A species with a partially filled outer shell

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21 mark

This question refers to isolated gaseous species.

The species O2-, Ne and Mg2+ are isoelectronic. 

In which order do their radii increase?

 

Smallest               begin mathsize 28px style rightwards arrow end style                  Largest             

A

B

C

D

Mg2+

Ne 

Mg2+

O2-

O2-

O2-

Ne

Ne

Ne 

Mg2+

O2-

Mg2+

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31 mark

Which of the following has a complete subshell?

  • Mg

  • Si

  • Co

  • Cl

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11 mark

Which species produces a half-filled set of p orbitals on losing an electron?

  • Li+

  • F

  • N

  • N-

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21 mark

Which statement explains why electrons pair up in orbitals before occupying an orbital of a higher energy level?

  • The energy from repulsion is greater than the jump to a higher orbital.

  • Electrons occupy higher energy orbitals before lower energy orbitals.

  • Electrons in lower orbitals have higher energies.

  • The energy from repulsion is less than the jump to a higher orbital.

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31 mark

A charged particle has the electronic configuration [Ar]3d3.

What is the identity of the particle?

  • Cr+

  • V3+

  • Ti2+

  • V2+

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11 mark

There are six unpaired electrons in atoms of element Z. What could element Z be?

  • Sulfur

  • Iron

  • Carbon

  • Chromium

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21 mark

The diagram shows three orbitals labelled 1, 2 and 3.

1-1-q17-s-and-p-orbitals

What is the correct label for each orbital?

  • px, py and pz

  • s, pz and py

  • s, px and pz

  • s, px and py

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31 mark

What is the electronic configuration of the ion with a single negative charge and the atomic number 17?

  • 1s2 2s2 2p6 3s1 3p6

  • 1s2 2s2 2p6 3s2 3p6

  • 1s2 2s2 2p6 3s1 3p5

  • 1s2 2s2 2p6 3s2 3p5

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41 mark

What is the correct sequence for the orbitals shown in an atom of vanadium in order of decreasing energy?

  • 3s 3p 4s 3d

  • 4s 3d 3s 3p

  • 4s 3d 3p 3s

  • 3d 4s 3p 3s

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51 mark

What is the electronic configuration of the ion with a single negative charge and the atomic number 35?

  • 1s2 2s2 2p6 3s1 3p6

  • 1s2 2s2 2p6 3s2 3p5

  • 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p5

  • 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6

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